Semiconductor LEDs have largely replaced conventional incandescent, fluorescent and halogen lighting sources in many applications due to their long life, ruggedness, color rendering, efficacy, and compatibility with other solid state devices. In marine applications, for example, light emitting diodes (LEDs) are emerging as a desired light source for their energy efficiency, instant on-off characteristics, color purity, and vibration resistance.
LEDs are an efficient light source widely available, having surpassed High Intensity Discharge (HID) lamps in lumens per watt. Different uses of LEDs in various light applications, including use of LEDs in marine environments, offer unique advantages and disadvantages.
For example, LEDs designed to deliver high levels of brightness suffer from problems associated with heat dissipation and inefficient distribution of light for certain applications. While these high brightness LEDs are significantly more efficient than incandescent systems or gas-filled (halogen or fluorescent) systems, they still dissipate on the order of 50% of their energy in heat. If this heat is not managed, it can induce thermal-runaway conditions within the LED, resulting in their failure. For situations requiring high levels of lighting, this situation is aggravated by combining many high brightness LEDs in a tight geometrical pattern within a light-source structure. Heat management becomes a primary constraint for applications seeking to use the other advantages of high brightness LEDs as a source of illumination.
For example, underwater lighting devices that use LEDs may require configurations that compensate for ambient pressure and/or rising internal temperature in order to avoid catastrophic failure of all or a portion of the lighting device. Such configurations may use a pressure-protected housing to isolate the LEDs from the ambient pressure, or may immerse the LEDs in a fluid-filled temperature compensation environment to provide thermal management.
However, the disadvantages of fluid-filling an LED light may include decreased light beam control and increased contamination of the LED phosphor coating. Thus, protecting LEDs from the external pressure and excess internal temperature using a pressure-protected and thermally-efficient housing is desired.
Accordingly, there is a need in the art to address the above-described and other problems.